


Anaconda

by dabbling_dood



Category: Gravity Falls
Genre: Anal Fingering, Anal Sex, Bondage, Dirty Talk, Dom/sub Undertones, Human/Monster Romance, M/M, Monster sex, Naga Bill Cipher, Teasing, predator/prey play
Language: English
Status: Completed
Published: 2018-08-15
Updated: 2018-08-15
Packaged: 2019-06-22 15:12:37
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,566
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15584706
Author URL: https://archiveofourown.org/users/dabbling_dood/pseuds/dabbling_dood
Summary: “Do I want to fuck a giant snake?” Dipper says, raising his brows.  “Sure.  Let’s go for it.”~AKA the Naga AU where the snake gets in Dipper's pants.





	Anaconda

**Author's Note:**

> The Naga AU you didn't ask for, but you're reading it anyway. You nasty monster fuckers.  
> This has been in progress for ages (along with the rest of my smut-shots), and I finally finished it while taking a break from my Superpower AU fic. Enjoy, peeps.

Dipper should know better than to initiate a play-fight with a giant snake.  It doesn’t matter that Bill’s upper half could pass for human, if not for the patches of gold scales.  And the claws.  And the slit pupils.  Not to mention the fangs—hard to miss those, since Bill flashes a toothy grin every thirty seconds—and the awful snake jokes.

( _God,_ the snake jokes.  It took a month for Bill to stop singing _Anaconda_.  Dipper will never forgive Mabel for introducing him to it.)

No, Dipper has no excuse for forgetting that Bill is a giant snake.  That’s not the biggest problem, though.

“Give up yet, kid?” Bill asks, propping his chin on his hand like he’s having a casual conversation and not looping his snake half around a thrashing Dipper.  Dipper swears.  Bill squeezes the breath out of him.  When Dipper kicks at Bill’s upper body, Bill wraps the loose end of his tail around Dipper’s legs.  Dipper groans and slumps into the coils as Bill drags him into arm’s reach.

“Showoff,” Dipper grumbles.  “Let me loose.”

Bill makes a show of thinking it over.  “Nah.”

The biggest problem isn’t that Dipper forgot Bill is a snake.  He also forgot that Bill is an asshole.

“You’re an asshole,” Dipper says, because he’s out of breath and clever commentary.

Bill shrugs, beaming, and props Dipper upright against the wall of the cave he calls home.  Dipper tries sliding his arms loose.  No dice; that only works when Bill is distracted.

A few months ago, Dipper would’ve panicked.  First impressions have a hell of an impact, and Bill introduced himself by ambushing Dipper and dragging him into his cave, where Dipper thought he’d be eaten alive.  Instead, Bill asked about the journal he had recognized as Ford’s.  Talk about a lucky break.

The fact that Dipper can settle into the coils of the two-hundred foot naga who ambushed him is a testament to weeks of self-imposed exposure therapy.

“Let’s make a deal,” Bill announces, and Dipper settles back with a roll of his eyes.  It’s a good thing he’s comfortable.  If he knows Bill—and he does—the slithery prick wants to exchange something for Dipper’s freedom.  That means a long conversation because Dipper is stubborn as hell.

Bill throws an arm over Dipper’s shoulders.  “I’ll let you go if you do me a little favor.”

Called it.

“Specifics, Bill,” Dipper reminds him flatly.  He keeps his eyes on the cave wall instead of on Bill—not because of the bare, well-muscled torso on display, but because attention only encourages him.  Bill is insufferable no matter what he looks like.  He is also half snake.  Snakes are not attractive.

No, Dipper has not thought about this before.

“It’s just a small favor,” Bill is saying.  “Completely innocent.  Easy enough that you could do it right here without breaking a sweat.”

“Are you eventually going to tell me what this favor is?”

“Are you going to take the deal?”

Dipper groans, head drooping forward.  Bill is being particularly evasive today.  Great.

“We both know how this is gonna turn out.  Can we skip to the part where you name your price and get your tail off me?” Dipper tries.

Grinning, Bill gives Dipper a squeeze with his coils, and Dipper grunts at the friction teasing certain areas.  Dangerous heat simmers under his skin.  It bubbles higher every time Bill’s coils shift around Dipper’s thighs, practically cupping his ass and brushing his groin.

“Why don’t we throw in some variety this time?” Bill says.

“By skipping the deal?”

“Or skipping the bargaining.  You could agree to the deal as-is.”

When Dipper squirms, Bill tightens his hold.  Dipper stops struggling before Bill can rub against something sensitive.  Bill loosens up.  The movement makes Dipper squirm.  Rinse and repeat.

This isn’t necessarily sexual for Bill, and Dipper _knows_ this.  Bill just likes contact.  The sense of intimacy is an unfortunate side effect from the exposure therapy, from huddling against Bill while that long tail wrapped around his ankle, or his arm, or his thigh; from slowing his breathing to match the rhythmic stroke of Bill’s hand on his back; from falling asleep to Bill’s heartbeat, pillowed against his coils.

Bill’s tail still occasionally sets off Dipper’s triple-F reflex—fight, flight, or freeze—but the three F’s have recently become four.

That’s a fucking problem.

“It’s only a small favor,” Bill presses when Dipper doesn’t speak up.  “I’m not gonna _eat_ you.”

“We’ve established that,” Dipper grumbles.  His voice sounds strained.

Bill loosens his hold, a frown shoving the grin off his face.  “You can breathe, right?”

“Yeah.”

“You sure?  You won’t be much fun if I crack your ribcage like a walnut.”

“I’m fine.  It’s not that tight.”  Although Dipper should take the opportunity to slip free, he only squirms until Bill is snug around him again.  “So, about this favor of yours…”

Bill’s grin returns with a vengeance.  “Am I hearing an agreement?”

“Not until I know what the favor is.”

“Boo, you whore,” Bill whines.  He says it in the exact same tone that Mabel does.  “Fine.  You have to close your eyes for…let’s see…ten seconds.”

Dipper immediately squints at him.  “Why?”

“Ah-ah-ah.  That’ll ruin the surprise.  I want to try something.”

“Is this going to freak me out?”

“I won’t scare you or put anything gross on you,” Bill huffs, as if Dipper is being unreasonable and not, say, speaking from experience.

“Is it going to hurt?”

“No!”

“Is it going to make me angry?”

Bill looks vaguely disturbed.  “I hope not.”

Dipper could keep pushing for clues, but what he has is vague, and Bill has piqued his curiosity.  Besides, the faster Dipper gets loose, the better.  He’s handled Bill’s pranks before.  He has _not_ handled an unscheduled visit from the boner fairy.

Sighing, Dipper says, “You’ll let me go, and I’ll close my eyes for ten seconds?”

“You close your eyes for ten seconds, and _then_ I’ll let you go.”

Dipper raises a brow.  “You’re really not going to freak me out?”

“Yeesh, kid, trust me a little.”  Bill has the nerve to look offended.

Rolling his eyes, Dipper caves, “Fine.  Deal.”

Bill grins.  “Always a pleasure.  Close the peepers, Pine Tree.”

Dipper gives Bill one last, probing look before doing as he’s told.  He braces himself as Bill shifts beside him.  He fights back warm shivers as Bill’s breath brushes his face.  His eyes fly open as Bill’s mouth presses over his.

Dipper’s lips part around his shock.  Before Bill draws back, the tip of his tongue flutters over Dipper’s lower lip, and Dipper chases his mouth as they part.

Bill shoots him a pout that is more smug than indignant.  “That wasn’t ten seconds, Pine Tree.”

Dipper mixes a laugh with a scoff.  His face is growing warmer by the second, but the bioluminescent moss lining the cave makes him look red anyway.  “Come here and let me try again.”

Beaming, Bill dives into another kiss.  Dipper squirms closer.  Bill’s coils shift around him, and Dipper doesn’t have to look to know there’s a hand steadily creeping toward his nether regions.  Bill nips Dipper’s bottom lip.  Dipper traces Bill’s teeth with his tongue.  As Bill deepens the kiss, his coils pull Dipper flush against him.  His hand brushes Dipper’s crotch.

Dipper startles.  The part of Bill’s tail cupping his ass is definitely squeezing with purpose now.  Disentangling his tail from Dipper’s legs, Bill tugs Dipper into his lap.  Dipper rocks his hips.

“Is that a snake in your pants, or are you just happy to see me?” Bill asks, and Dipper groans.

“You just couldn’t resist, could you?”

“Did you expect any less?”

“I was hoping I’d found a way to shut you up,” Dipper says drily.  At Bill’s answering scoff, he nuzzles against his neck.  “Are you gonna let me loose?”

“Oh, I don’t know. You’re trash-talking me an awful lot, and I’m still not sure you kept your eyes closed for ten seconds.”

Dipper snorts.  “Just admit you like having me wrapped up like this.”

“I do like you like this,” Bill agrees easily, giving Dipper a squeeze.  His hands explore Dipper’s squirming lower half.  “Completely helpless.  At my mercy.  I love it.”

All the blood in Dipper’s body gets sucked down to his cock.  Bill raises his brows when Dipper’s hips jerk, and the grin stretching across his face sends shivers down Dipper’s spine.

“ _Ooh_ ,” Bill purrs, “somebody’s got a kink.”

“Look who’s talking,” Dipper huffs.

“You’re going to be so much fun, I can tell.  You’ll look so pretty when you beg.”

“You think you can make me beg?”

“I think I can make you _scream_ ,” Bill grins, rocking Dipper’s hips with his hands. 

Dipper lets out a shuddery breath.  This is going faster than he’s used to, but at this point, he doesn’t care.  “Where’s your…?”

“My anaconda?”

“I swear to god, if you start singing that song—”

“Relax, kid.  My dick, if you _insist_ on the technical term, doesn’t hang loose like you humans’.  It comes out of a slit.”

“Oh.”  Dipper hesitates.  “Um, how big is it?”

Bill cocks his head, looking amused. “You’re imagining something ridiculous, aren’t you?”

“I don’t have experience with _snakes_ ,” Dipper says defensively.  “For all I know, the average naga dick could be a three-foot monstrosity.”

“I don’t have a three-foot dick,” Bill scoffs.  “It’s only two feet.”

Dipper’s jaw drops.  Bill bursts out laughing.

“ _Geez_ , kid, you’re making this too easy for me!”

Groaning, Dipper shoves Bill with his shoulder.

Bill nuzzles his face.  “You really wanna do this?”

“Do I want to fuck a giant snake?” Dipper says, raising his brows.  “Sure.  Let’s go for it.”

_“Yes_.”  Fumbling with Dipper’s fly, Bill practically tears the pants off him.  Dipper squawks as Bill’s claws rip his boxers.

“Dude!”

“Whoops, sorry.”  Bill tosses the clothing aside and starts on Dipper’s jacket, coils unwrapping Dipper’s torso so they can gather around his arms and raise them over his head.  Tossing aside the jacket, Bill presses the hem of Dipper’s shirt between his teeth.  “Hold this for me.”

“Kinky bastard,” Dipper replies, muffled.  He sighs when Bill’s hands run over his front.  Bill tweaks his nipples, and Dipper twitches.

“Feel good?” Bill does it again.  Dipper moans quietly, arching into the touch.  Grinning, Bill coaxes Dipper’s arms up and back until Dipper is drawn into a taut curve, one of Bill’s hands supporting his back.  Bill’s mouth seals over a nipple.  Dipper shudders.

“Fuck, fuck—Bill…”  Bill flicks his tongue, and Dipper jerks.  “Please tell me there’s lube— _ah_ —s-somewhere in that junk heap.”

Bill makes an affronted sound, pulling off of Dipper’s chest with a wet smack.  “It’s not a junk heap!”

“Do you have lube or not, packrat?”

“You’re mouthy for someone in your position,” Bill huffs, lips twitching.  “I’ll have to fix that.  C’mere.”

He releases Dipper’s arms and hauls him over one shoulder, making Dipper grunt.  “Bill. Lu-u-ube.”

“I heard you.”  They’re moving deeper into the cave, where Bill’s nest sits surrounded by a collection of matchboxes, billiards balls, dentures, padlocks, and lava lamps; taxidermied animals, Summerween decorations, and cutlery ranging from decorative spoons to plastic sporks; compasses, pacifiers, and things Dipper can’t even name.

Bill lets Dipper down and rummages through a jewelry cabinet with a broken hinge.  Dipper tries not to look at the glass eye collection nearby, instinctively drawing the hem of his shirt over his groin, while Bill gathers an armful of bottles.

“Take your pick.  I recommend mango,” Bill chirps, holding it up.

Dipper blinks at the labels on the tubes, a smile tugging at his mouth.  “All flavored ones?”

“Gotta be honest, kid,” Bill replies, “I snagged these before I knew what they were for.”

Dipper snorts, running a hand over his face.  “Breaking into adult stores, now?”

“I break into lots of places.  Now pick a flavor.”

Shaking his head, Dipper takes the mango one.  “Condoms?”

Bill responds with a blank stare.  Dipper makes a vague explanatory gesture.  “They’re like little sleeves that go on your junk.  Prevents STDs, pregnancy, stuff like that?”  Bill still looks confused.  “Little foil packets about this big?  They’re usually packed in boxes.”

“Oh!” Bill shoves the lube bottles at Dipper and paws through one of the niches carved into the cave wall.  He knocks a bag of water balloons aside before he returns with a couple of boxes, triumphantly extracting a foil packet.  “You mean these babies.”

“You thought they were balloons,” Dipper chokes.

“Good ones, too.  You should see ‘em inflate,” Bill replies shamelessly.  “Anything else we need for your intricate mating rituals, or am I all set to fuck you senseless?”

“I think we’re good,” Dipper says, still laughing.  Bill beams and grabs him with his tail again.

The cushions, pillows, and plush toys lining one side of Bill’s nest tumble over as Bill tosses the fluffiest ones into a pile, coaxing Dipper down onto them.

“Walk me through the condom thing.  You said it goes on my dick, right?” Bill says, inspecting the foil packet.  Dipper opens his mouth to answer, but the tail winding up his leg distracts him.  “So I just rip it open, unroll it, and put it on?”

“Uh—n-not quite.”  Dipper has Bill’s tail wrapped around his leg and torso now.  He’s let Bill trap his arms at his waist, and his shirt has gotten pushed up over his chest again.  “You don’t need it until you’re ready to— _nnh, fu-u-uck me!_ ”

The last bit comes out as a moan, and Dipper jerks.  Grinning, Bill squeezes the hand on Dipper’s cock.

“Not until the main event, huh?  Hope you can still think clearly by then.  I’m gonna play with you first.”

Bill sets aside the condom and the lube, licking his lips.  His coils squeeze.  Grunting, Dipper squirms as Bill licks a long stripe up his chest, pushes his shirt higher, and then tears it open.  Dipper yelps.

“Dammit, Bi—Bill!” he groans, but there’s no heat to it, not with Bill’s mouth sealed over his nipple.  Bill pushes his legs apart.

“You sound so good, kid.  I’ve barely started teasing you.”  Bill presses his hips to Dipper’s, trapping Dipper’s cock between them.  He rocks slowly, and Dipper shudders.

“Oh, god.  You—are you still not hard?”

“I have outstanding self-control.  Plus, your naughty bits are easier to reach than mine.”

“Are you just gonna tease me all day?” Dipper whines, voice cracking as Bill pushes his legs further apart.

“Tempting!” Bill chirps.

Dipper struggles to free his arms, but Bill’s coils tighten.  “Bill, come _o-o-on_ … You already have me where you want me.  Eat me already.”

Bill freezes up.  His hands clench around Dipper’s thighs.  If Dipper wasn’t giving Bill the brightest doe eyes he can muster, he would have missed Bill’s pupils dilating.  Bill huffs a breathless laugh and says, “Careful, Pine Tree.”

The corners of Dipper’s mouth twitch.  “Oops.  I really shouldn’t provoke you.  I am your prey, after all.”

Bill narrows his eyes.  “Pine Tree.”

“What, am I struggling too much?”  Dipper squirms, gasping when Bill tightens around him.  “Oh, I’m so helpless.  You could just eat me up.”

“Dammit, kid…” Bill grinds out.

“You just tore off my clothes and started touching me all over, and I can’t do a thing.  I guess I’d better keep your mind off of how hot and tight I’d be around your cock, huh?  Since I’m at your mercy and all.”

Bill clamps a hand over Dipper’s mouth.  His face is a strange mix of strain and elation.  “Kid, you’re on thin ice right now.”

Arching his back, Dipper lets out an exaggerated moan through Bill’s hand.  Bill’s jaw goes slack.  His fingers drag over Dipper’s lips as he lets go.

“Please don’t fuck me senseless, Mister Predator,” Dipper mewls.  “Please don’t finger me open for your big, hard cock.  Don’t make me beg and scream and writhe—”

Bill growls something that sounds like “fucking shameless” before he gags Dipper with ferocious kisses.  Moaning, Dipper sinks into the heady feeling of being overpowered, taken, and indulged in.  Bill’s hips grind against his.  There’s something else down there, a lump growing more and more prominent against the crook of Dipper’s thigh.

When Bill finishes dominating Dipper’s mouth, he reaches between them to give himself a few pumps.  Dipper looks down, apprehensive.

“Oh,” Dipper says.  Bill raises his brows at him, and Dipper quickly explains, “I was expecting something weirder.”

“Like what?  An actual anaconda?”

Dipper laughs.  “I don't know.  Uh, I should show you how to use the condom, now that you're…”  He nods at Bill's surprisingly normal dick.  “…out.”

Although Bill automatically tightens his hold when Dipper tries to get loose, he lets him free one arm.  Bill hands him the condom.

“I’m gonna need both hands, Bill.”

“Killjoy,” Bill pouts, but the coils around Dipper relax, leaving him loosely restrained.

Dipper makes no move to disentangle himself as he sits up.  He clears his throat.  “Um, so, first of all, you want to check for holes.”

Bill watches Dipper hold the condom up to the brightest patch of luminous moss, nod, and unwrap it.  “You’re not gonna unroll it?”

“Not until you put it on.”

“How many steps are there to this thing?”

“Shut up and watch.  Can I touch you?”  Dipper gestures at Bill’s dick, and Bill happily scoots forward.  Dipper wraps his hand around it.  Bill closes his eyes and lets out a sigh as Dipper explores the textured surface, from the swollen head to the thick base protruding through a slit.  The girth makes Dipper lick his lips.  Beneath it, Dipper can feel a bulge in Bill’s skin, almost pushing out with his dick.  Testicles, probably.  Bill twitches when Dipper rubs there.

“Easy, tiger,” Bill says, guiding Dipper back up his cock.  “Show me how the condom thing works before we get crazy, here.”

Snickering, Dipper gives Bill’s cock one more stroke.  “You pinch the tip of the condom—just that much—and then you just roll it on.  It’s not too tight, is it?”

Bill blinks.  “No, it’s…  Huh.  That’s kinda weird.”

“You’ll get used to it,” Dipper says, brushing Bill’s hand away when he tries to touch it.  “Careful.  Your claws.”

“I know how to touch my dick without scratching it, Pine Tree.  You, on the other hand…”

Bill’s coils suddenly tighten around Dipper, making him gasp.

“Didn’t you mention something about fingering you open for my ‘big, hard cock’?” Bill grins.  Dipper moans as the tips of Bill’s claws drag up his chest and throat.  One hooks under his chin and tips his face up.  “That’s not gonna be comfortable, kid.  You don’t want me scratching up your insides.”

“Y-yeah, no,” Dipper chokes out.  “I can—I can do it.”

Bill nuzzles his face.  “That’s what I like to hear. Turn around and bend over for me.”

Dipper doesn’t follow Bill’s instructions so much as Bill maneuvers him around.  With his head and shoulders resting against the cushions, Dipper pokes out his ass and wriggles his trapped arms until he can press tentatively against his hole.

“The lube,” Dipper says, just as the pop of a cap reaches his ears.

“I’ve got it.”  Bill taps Dipper’s hand with the tube.  Dipper cups his palm, and a glob of fluid squirts into it.  “Tell me when you need more.  Now, give me a show.”

Shivering, Dipper works the lube between his hands before rubbing a slick path between his cheeks.  Bill strokes his thighs.  Dipper spreads his legs further apart.  When he slips a finger past his rim, Bill’s hands slide up to cup his ass, spreading him open and leaving him shuddering as he works his finger deeper.

Bill makes a low, hungry sound.  “You do this a lot, don’tcha?”  It’s barely a question.  Dipper responds with a quiet moan, flexing his finger inside himself.  It’s easy to find the spot that makes his hips jerk and his cock leak.

“A little more,” Dipper gasps, holding his free hand palm-up.  Bill gives him more lube.  Giving his prostate another prod, Dipper extracts his finger, slicks up again, and quickly works two fingers into himself.  He hisses at the resistance.

“Easy, Pine Tree.”  Bill grabs his wrist, but Dipper is already three knuckles deep, stroking his prostate with little gasps and moans.

“S’okay,” Dipper says, fingers moving, eyes closed.  “It’s okay.  _Ah_.  I do this a lot.”

“No kidding.  Gods, look at that…”

Bill pulls on Dipper’s wrist to guide his fingers in and out of him.  Dipper moans as Bill fucks him with his own fingers.  When Dipper guides a third finger inside, Bill squeezes his ass impatiently, the condom slippery against Dipper’s inner thigh.

“The lube,” Dipper says, breathless.  “It is water-based, right?”

“Dunno.  Hold on.”  While Bill checks the label, Dipper stretches himself as far as three fingers will go.  It’s not as much as Dipper wants, but it still makes him moan.  “Yep, there it is.  Water-based.  …Enjoying yourself, there?”

Dipper removes his fingers, groaning.  “Put…  O-on the condom, put more lube…  Need you inside…”

“Yeah?  Is that why you keep clenching?” Bill teases, dragging a knuckle over Dipper’s rim.  “Want me to fill you up?”

“Please,” Dipper begs.

“I dunno.  You’re so fun to tease,” Bill replies, but Dipper can hear slick noises, and the coils around him pull him back into Bill’s lap.  He squirms as the tip of Bill’s cock presses against his hole.  “Last chance to get away, Pine Tree.”

“Bill, fuck me!”

Squeezing Dipper’s hips, Bill lowers him onto his cock.  Dipper’s body opens up for the head and clamps around the shaft, which widens until Dipper is straining to take it in.  Bill hisses as Dipper settles into his lap.

“You okay?” Bill gasps.

Dipper moans in reply, hips twitching.  “Feels good…”

Bill squeezes Dipper’s thighs.  His coils flex intermittently, and Dipper rocks in his lap.  When one of Bill’s hands wraps around Dipper’s cock, Dipper jerks, choking out a string of wordless cries.

“Bill!” he manages.  “Don’t—I ca—I can’t last if you— _oh, god!”_

Bill mouths at his neck.  “Can I move?”

“Yes, please move!”

Bill lets go of Dipper’s cock to hold his hips still, and the coils restraining Dipper lift him off of Bill’s lap.  The head of Bill’s cock drags against Dipper’s inner walls.  It’s just enough pleasure to make Dipper ache for more.

“Scream for me, Pine Tree,” Bill says, and he slams Dipper down on his cock.

Dipper’s cries ring through the cavern.  With every thrust, Bill rubs against Dipper’s sweet spot and fills him up more than fingers ever could.  Bill is certainly driving the pace, but Dipper has some control.  He fucks himself on Bill’s cock as hard as he can.

“More,” Dipper wails.  “Don’t stop, don’t stop!  Take me!”

“You like that?  _Uhn…_   You like when I ruin you?  You like getting caught and fucked?”

“Yes, I love it!  I want more!”

Bill’s hands hook under Dipper’s knees, and Dipper makes a broken noise as Bill lifts his legs up and open.  Bill is supporting Dipper’s weight completely and _still_ bouncing him on his cock with that powerful set of coils.  The end of Bill’s tail wraps around one of Dipper’s thighs.  While it holds him open, Bill uses his free hand to palm Dipper’s dick.

Dipper spasms.  “ _Bill!”_

“Come on,” Bill rasps.  “Give in for me, Pine Tree.  Wanna feel you fall apart.  Wanna feel you come.”

“I’m clo- _ose!”_ Dipper cries, writhing in Bill’s grasp. 

Claws dig into his hip, but it gets lost in the pleasure.  His head falls back against Bill’s shoulder.  With Bill panting against his neck, Dipper shudders closer and closer to the tipping point.

Bill makes a stained, breathy sound.  Dipper can barely process the words when Bill gasps, “ _Fuck_.  Can I—inside—?”

Dipper jerks.  “Yeah—yeah, fill me up—”

Bill interrupts with a guttural groan, coils squeezing around Dipper until he can barely breathe, shudders rolling through him.  Dipper feels Bill’s cock pulse.  Then, the tension drains from Bill’s body, and his rhythm with it.  The coils loosen.  His hand is still tugging lazily at Dipper’s cock, but Dipper feels like a car rolling to a stop inches from the finish line.

“Bill, please—Bill, _please_ , I’m so _close_ , please—!”  Dipper’s voice sounds like a compound fracture.

When Bill presses him into the pillows, ass in the air—and thank whatever deity is listening that Bill hasn’t pulled out yet—Dipper ruts into his hand without so much as a passing thought for the claws, even when Bill’s other hand squeezes the back of his neck.  And finally, Dipper dissolves into screams.

Bill hisses, twitching.  It’s fuzzy through the orgasm.  Some part of Dipper’s brain is functional enough to mumble about the post-coital sensitivity, how Dipper probably feels like a vise right now.  That part of Dipper’s brain gets interrupted with every throb of pleasure.  It gives up long before Bill curls up with him.

“Damn,” Bill pants.  “That felt good.”

Dipper puts all his strength into nodding.  Aside from his heartbeat, which vibrates from his ribcage all the way up to his throat, slow motion has become his default setting.  He makes a quiet sound of complaint when Bill’s cock slides out of him.  Bill nuzzles his hair.

“Can I take off the condom now?” Bill asks breathlessly.

Dipper grunts, blinking his eyes open.  “You’ve gotta, uh, tie it.  Here, let me…”

Rolling over, Dipper slides off the condom and ties a knot in it.  Somewhere between tossing it at the nearest novelty trash bin and sinking into the cushions again, Dipper sees Bill tucking his cock back into the slit it came from.  Something makes his groggy brain fall over itself.

“Is that…?”  Dipper squints down at Bill’s groin.  He counts—one, two.  “Oh my god.”

Bill hums quizzically, smoothing down the _second cock_ barely poking out of his slit.  “What?”

“You have _two?_ ”

Bill frowns, looks down at himself, and then laughs.  “ _Oh._   Yeah, I…  That’s new for you, huh?  Forgot about that.”

“You _forgot?_ ” Dipper says, bursting into giggles.  Bill gathers him closer, and Dipper hooks a leg around his waist, still giggling as he snuggles up.  “You forgot you had an extra dick.”

“ _You’re_ an extra dick,” Bill says.

Dipper starts laughing harder.  “But you—Bill.  _Bill_.  That means you have _two extra dicks._ ”

It takes them a while to quiet down.

When Bill shifts beside him, Dipper is too drowsy to notice.  It’s only when Bill props himself up, coils squeezing Dipper closer, that Dipper rouses himself long enough to see Bill furrowing his brow at the tunnel.

“What’s up?” Dipper asks, voice rough and sleepy.

Bill sits up further.  “There’s someone—”

Then a screeching voice echoes through the burrow.  “ _Ohmigod_ BILL CIPHER, DID YOU EAT MY BROTHER?!”

Dipper sits bolt upright.  As footsteps pound closer, he sends Bill a panicked look.

“Uh.”  Bill huffs out a startled laugh and calls back, “Not in the traditional sense!”

When Mabel appears in the mouth of the tunnel, holding Dipper’s torn clothes and her grappling hook, Bill is buried under the mound of pillows Dipper keeps throwing at him, laughing so hard he can’t breathe.

 

**Author's Note:**

> You're still nasty monster fuckers. Also, don't ask why Bill knows about lube but not condoms. He probably only reads labels when he's bored.  
> Want art? Check the "naga au" tag on my Tumblr, doodling-dood.


End file.
